I don’t own a car and I ride my bike a lot, often on very busy city streets. I always wear a helmet when I ride — not because it makes me less likely to get hit by a car, but because it makes me less likely to suffer from brain damage if and when I do get hit by a car.
However, as Dave Walker (@davewalker) points out, there are MANY other and much better ways to make cycling safer for everyone. 🚲